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Home charge tripping breaker: Anyone?

james2441139

Member
Apr 8, 2021
32
16
Seattle
Are you saying the only way to set the current is with an app? The Tesla HPWC has internal dip switches to set the maximum current. Without seeing a schematic I can only guess what they are doing.
Program the current with the EVSE not connected to the car. The car is only going to ask the EVSE once what the maximum value is for a given connection. If it is changed after that the car won't know it was changed. The question is does the EVSE have high current limiters or just a logic system that tells the car what the maximum is but has no way to enforce the current draw maximum? My guess, as a retired electrical/computer engineer, is the latter. The HPWC does it with dip switches so it can't be changed dynamically.
@murphyS90D , you are correct for the Gen2 Tesla wall charger but the Gen3 does not have a physical switch anymore. The configuration of things like maximum power is done through a web page. This is why electricians insist on putting a 60A breaker, to support the potential maximum 48A delivery... because the configuration page is technically accessible by the end user.
I don't know how the ChargePoint works but it seems to be a web page too?

I otherwise agree with you, obviously, about setting the maximum on the charger with nothing plugged :)

Yes the ChargePoint does not have any physical switch to regulate current. So it needs to be powered on and then can be changed thorough the app. I changed it to max 40A (breaker current, the app has options for 40A and 50A), and then connected to the car. The breaker tripped again within couple seconds.
 

captjoemcd

Member
Nov 29, 2019
258
288
California
Is the breaker in your panel a GFCI breaker or not?

Since you’ve lowered the max draw on the car to 32A and it’s still popping the breaker, you’ve got something else going on - doesn’t seem like standard overcurrent popping the breaker. Could be wiring issue or internal to the ChargePoint.

do you have a voltmeter? What’s L1-ground, L2-ground, and L1-L2?
 

captjoemcd

Member
Nov 29, 2019
258
288
California
Is the breaker in your panel a GFCI breaker or not?

Since you’ve lowered the max draw on the car to 32A and it’s still popping the breaker, you’ve got something else going on - doesn’t seem like standard overcurrent popping the breaker. Could be wiring issue or internal to the ChargePoint.

do you have a voltmeter? What’s L1-ground, L2-ground, and L1-L2?
1624391716830.jpeg
 

james2441139

Member
Apr 8, 2021
32
16
Seattle
Yes the breaker has GFCI and that what I think possibly the issue is. I dont know what could be the best strategy for me here: swap the breaker with a non-GFCI (and therefore non-compliance with NEC?), figure out a way to disable GFCI in the ChargePoint (does not look like its possible), hardwire it, or continue using the Tesla UMC (and live with a 32A vs the 40A max the ChargePoint plugged in).
 

dannycamps

Member
Apr 8, 2019
733
661
Northeast USA
The Tesla HPWC has internal dip switches to set the maximum current.

I believe the Gen3 does not have any dip switches and can only be set by connecting to the unit's internal wifi network.

Yes the breaker has GFCI and that what I think possibly the issue is. I dont know what could be the best strategy for me here: swap the breaker with a non-GFCI (and therefore non-compliance with NEC?), figure out a way to disable GFCI in the ChargePoint (does not look like its possible), hardwire it, or continue using the Tesla UMC (and live with a 32A vs the 40A max the ChargePoint plugged in).

I fail to see how hardwiring can help in this case. If the breaker is a GFCI breaker, regardless of whether the ChargePoint is hardwired or plugged into an outlet, it is still going to go through the GFCI breaker.
 

captjoemcd

Member
Nov 29, 2019
258
288
California
I believe the Gen3 does not have any dip switches and can only be set by connecting to the unit's internal wifi network.



I fail to see how hardwiring can help in this case. If the breaker is a GFCI breaker, regardless of whether the ChargePoint is hardwired or plugged into an outlet, it is still going to go through the GFCI breaker.
I'd agree, the only thing that gives me a little pause is the language from ChargePoint which makes me think there may be some odd behavior they've seen.

Nonetheless, hardwiring removes the requirement for the GFCI breaker which is newly required on 240 receptacles of all amperages as of the 2020 NEC.

OP - Has your AHJ adopted the 2020 NEC or are they still on 2017? Sometimes there’s a delay in adoption in which case you'd be fine, code-wise, with not swapping the breaker. If I were in your shoes, I'd (temporarily ;) swap the breaker for a non-GFCI and see if it behaves, and then decide from there
 

brkaus

Well-Known Member
Jul 8, 2014
8,036
6,515
Austin, TX
It’s pretty common for multiple gfci breakers in series to cause tripping. The gfci within the evse is causing a very small amount of current to flow through the ground to test the circuit. That current is tripping the gfci in the breaker.

you have the following options -

1. Try a different gfci breaker. Some are more sensitive.
2. Replace the gfci breaker with a regular breaker. This will be against NEC.
3. Replace the gfci breaker with a regular breaker & remove the plug and hardwire the EVSE.

did you put the plug in the EVSE? You can also check that it is wired correctly.
 
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james2441139

Member
Apr 8, 2021
32
16
Seattle
It’s pretty common for multiple gfci breakers in series to cause tripping. The gfci within the evse is causing a very small amount of current to flow through the ground to test the circuit. That current is tripping the gfci in the breaker.

you have the following options -

1. Try a different gfci breaker. Some are more sensitive.
2. Replace the gfci breaker with a regular breaker. This will be against NEC.
3. Replace the gfci breaker with a regular breaker & remove the plug and hardwire the EVSE.

did you put the plug in the EVSE? You can also check that it is wired correctly.
Thanks yes I am going to get another GFCI breaker to try. Don't really want to hardware it.
I didn't put the plug in the EVSE , just connected the charging wire that goes to the car. Checked that already, no problems there.
 

RickParker

Member
Nov 3, 2020
82
151
Flower Mound
Wire connections loosen up after a bit of time. If you don't have the skill set to open up the NEMA or panel to tighten up your connections on both ends, hire an electrician. If you do it yourself while you have the panel open check other circuit connections, you'll be surprised just how loose some are, insulated quality screw driver and tighten all of them while you're there. I am a retired spark chaser (high voltage lineman specialist electrician). Likelihood is the #6 wire is stranded copper which is notorious for vibrating loose on install especially if you don't have the proper crimped ends. Occam's Razor - sometimes the simplest solution to a problem hss the easiest solution. As for ChargePoint and dip switches - I have no knowledge of them as I don't have experience. Good Luck. I think we'd all be interested to know the ending.
 
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james2441139

Member
Apr 8, 2021
32
16
Seattle
UPDATE: so I went ahead and tried three different GFCI breakers to see if the sensitivity variations make any difference in tripping or even stop tripping. I tried an Eaton, Square D, and Murray (all 50A 2 poles). All of them tripped. The Square D took about 7 seconds before tripping, the others (including my original GE GFCI 50A 2pole) tripped within couple seconds of connecting to the car.

I switched the GFCI to a non-GFCI Square D 50A 2pole breaker, and voila! The ChargePoint charges normally, with no lapse, no issues. Charging at 40A. So although it is violating current NEC code for not being connected through a GFCI breaker, I am going to have to live with it until I can hardwire the ChargePoint.

TL;DR: EVSEs will not work nicely with GFCI. Either hardwire your EVSEs (so that you dont have to use a GFCI breaker), or use a non-GFCI (and risk a code violation, if you happen to be within the jurisdiction).
 
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captjoemcd

Member
Nov 29, 2019
258
288
California
2017 version of the NEC requires it for EV charging
Prior to 2020 NEC, GFCI was required for 120V 15A or 20A receptacles in certain locations (such as garage). 2020 NEC expanded it to circuits up to 250V and removed the amperage requirement. So a NEMA 14-50 50A 240V receptacle in the garage now requires GFCI whereas previously it wasn’t required. Hardwire devices do not require GFCI since there’s no place for someone to stick a fork.
 

captjoemcd

Member
Nov 29, 2019
258
288
California
UPDATE: so I went ahead and tried three different GFCI breakers to see if the sensitivity variations make any difference in tripping or even stop tripping. I tried an Eaton, Square D, and Murray (all 50A 2 poles). All of them tripped. The Square D took about 7 seconds before tripping, the others (including my original GE GFCI 50A 2pole) tripped within couple seconds of connecting to the car.

I switched the GFCI to a non-GFCI Square D 50A 2pole breaker, and voila! The ChargePoint charges normally, with no lapse, no issues. Charging at 40A. So although it is violating current NEC code for not being connected through a GFCI breaker, I am going to have to live with it until I can hardwire the ChargePoint.

TL;DR: EVSEs will not work nicely with GFCI. Either hardwire your EVSEs (so that you dont have to use a GFCI breaker), or use a non-GFCI (and risk a code violation, if you happen to be within the jurisdiction).
nice work and thanks for the the update!
 

brkaus

Well-Known Member
Jul 8, 2014
8,036
6,515
Austin, TX
This was added in 2017 - specific to EV use. Which is a bit silly to have the requirement for an outlet depend on its intended use. A 240v outlet has two phases that are each 120v to ground - and ground is specified as the reference.

1625708957833.png
 
Last edited:

captjoemcd

Member
Nov 29, 2019
258
288
California
This was added in 2017 - specific to EV use. Which is a bit silly to have the requirement for an outlet depend on its intended use. A 240v outlet has two phases that are each 120v to ground - and ground is specified as the reference.

View attachment 682420
Ah you’re totally right. I’ve never understood how that could be enforced in a residential setting. 2020 NEC made it a lot more cut and dry.
 
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